diff --git a/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler.test/models/jetbrains/mps/lang/typesystem2/samplechecker/handle/test/util.mps b/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler.test/models/jetbrains/mps/lang/typesystem2/samplechecker/handle/test/util.mps
index ba8a5e59..99d14797 100644
--- a/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler.test/models/jetbrains/mps/lang/typesystem2/samplechecker/handle/test/util.mps
+++ b/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler.test/models/jetbrains/mps/lang/typesystem2/samplechecker/handle/test/util.mps
@@ -11,7 +11,7 @@
     <import index="ie8e" ref="r:ab2605ab-b4bc-4e80-a8ca-19a4a8465c01(jetbrains.mps.logic.atom)" />
     <import index="4r4j" ref="r:94702bd0-f623-44e8-af0a-f2730f7d2518(jetbrains.mps.lang.typesystem2.samplechecker.handle.util)" />
     <import index="qrld" ref="r:2a79c8aa-e372-4c00-8d71-5d7f3db517e4(jetbrains.mps.logic.reactor.constraint)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
   </imports>
   <registry>
     <language id="f3061a53-9226-4cc5-a443-f952ceaf5816" name="jetbrains.mps.baseLanguage">
diff --git a/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler.util/models/jetbrains/mps/lang/typesystem2/samplechecker/handle/util.mps b/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler.util/models/jetbrains/mps/lang/typesystem2/samplechecker/handle/util.mps
index a3b687a2..356f199c 100644
--- a/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler.util/models/jetbrains/mps/lang/typesystem2/samplechecker/handle/util.mps
+++ b/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler.util/models/jetbrains/mps/lang/typesystem2/samplechecker/handle/util.mps
@@ -15,7 +15,7 @@
     <import index="wyt6" ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065/java:java.lang(JDK/)" />
     <import index="qrld" ref="r:2a79c8aa-e372-4c00-8d71-5d7f3db517e4(jetbrains.mps.logic.reactor.constraint)" />
     <import index="rchb" ref="r:f43ee4a0-488a-425a-87a0-594ab3b0d15f(jetbrains.mps.logic.reactor.program)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
   </imports>
   <registry>
     <language id="f3061a53-9226-4cc5-a443-f952ceaf5816" name="jetbrains.mps.baseLanguage">
diff --git a/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler/models/jetbrains/mps/lang/typesystem2/samplechecker/chr.mps b/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler/models/jetbrains/mps/lang/typesystem2/samplechecker/chr.mps
index b6b2650c..e62d718e 100644
--- a/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler/models/jetbrains/mps/lang/typesystem2/samplechecker/chr.mps
+++ b/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.samplechecker.handler/models/jetbrains/mps/lang/typesystem2/samplechecker/chr.mps
@@ -14,7 +14,7 @@
     <import index="ie8e" ref="r:ab2605ab-b4bc-4e80-a8ca-19a4a8465c01(jetbrains.mps.logic.atom)" />
     <import index="4r4j" ref="r:94702bd0-f623-44e8-af0a-f2730f7d2518(jetbrains.mps.lang.typesystem2.samplechecker.handle.util)" />
     <import index="xq5w" ref="r:729bada4-05fa-458f-8bf8-28b9cb978726(jetbrains.mps.logic.builtin.var)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
   </imports>
   <registry>
     <language id="f3061a53-9226-4cc5-a443-f952ceaf5816" name="jetbrains.mps.baseLanguage">
diff --git a/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.sampleplugin/models/jetbrains/mps/lang/typesystem2/sampleplugin/plugin.mps b/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.sampleplugin/models/jetbrains/mps/lang/typesystem2/sampleplugin/plugin.mps
index 47471670..6e9997fc 100644
--- a/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.sampleplugin/models/jetbrains/mps/lang/typesystem2/sampleplugin/plugin.mps
+++ b/languages/jetbrains.mps.lang.typesystem2/sandbox/jetbrains.mps.lang.typesystem2.sampleplugin/models/jetbrains/mps/lang/typesystem2/sampleplugin/plugin.mps
@@ -67,7 +67,7 @@
     <import index="45ys" ref="r:7365f7fe-12e6-4229-8901-f6dc6d5df03f(jetbrains.mps.logic.reactor.logical)" />
     <import index="qrld" ref="r:2a79c8aa-e372-4c00-8d71-5d7f3db517e4(jetbrains.mps.logic.reactor.constraint)" />
     <import index="i8dg" ref="r:e8529b97-a186-4c32-8f12-771b2a92b55a(jetbrains.mps.logic.reactor.rule)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
     <import index="tprs" ref="r:00000000-0000-4000-0000-011c895904a4(jetbrains.mps.ide.actions)" implicit="true" />
   </imports>
   <registry>
diff --git a/languages/jetbrains.mps.logic/jchr/models/jetbrains/mps/logic/jchr/constraint.mps b/languages/jetbrains.mps.logic/jchr/models/jetbrains/mps/logic/jchr/predicate.mps
similarity index 99%
rename from languages/jetbrains.mps.logic/jchr/models/jetbrains/mps/logic/jchr/constraint.mps
rename to languages/jetbrains.mps.logic/jchr/models/jetbrains/mps/logic/jchr/predicate.mps
index 0eef9ba7..9f7c8e69 100644
--- a/languages/jetbrains.mps.logic/jchr/models/jetbrains/mps/logic/jchr/constraint.mps
+++ b/languages/jetbrains.mps.logic/jchr/models/jetbrains/mps/logic/jchr/predicate.mps
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<model ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)">
+<model ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)">
   <persistence version="9" />
   <languages>
     <use id="fd392034-7849-419d-9071-12563d152375" name="jetbrains.mps.baseLanguage.closures" version="0" />
diff --git a/languages/jetbrains.mps.logic/jchr/models/jetbrains/mps/logic/jchr/program.mps b/languages/jetbrains.mps.logic/jchr/models/jetbrains/mps/logic/jchr/program.mps
index 651d1bf5..edea7f56 100644
--- a/languages/jetbrains.mps.logic/jchr/models/jetbrains/mps/logic/jchr/program.mps
+++ b/languages/jetbrains.mps.logic/jchr/models/jetbrains/mps/logic/jchr/program.mps
@@ -13,7 +13,7 @@
     <import index="oy3s" ref="r:a6030cee-34eb-4503-b1bf-015fe5cd8c1a(jetbrains.mps.logic.builtin.unification)" />
     <import index="xq5w" ref="r:729bada4-05fa-458f-8bf8-28b9cb978726(jetbrains.mps.logic.builtin.var)" />
     <import index="e2ud" ref="r:86a12676-9e8d-407a-83b6-a911ff5a7cf8(jetbrains.mps.logic.builtin.java)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
   </imports>
   <registry>
     <language id="f3061a53-9226-4cc5-a443-f952ceaf5816" name="jetbrains.mps.baseLanguage">
diff --git a/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/java.mps b/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/java.mps
index d97aeaef..fa5de0f6 100644
--- a/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/java.mps
+++ b/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/java.mps
@@ -10,7 +10,7 @@
     <import index="xq5w" ref="r:729bada4-05fa-458f-8bf8-28b9cb978726(jetbrains.mps.logic.builtin.var)" />
     <import index="eifs" ref="b984ee52-f34d-4b6d-8812-866c1d3eae31/java:runtime(jetbrains.mps.jchr.runtime/)" />
     <import index="f8dg" ref="b984ee52-f34d-4b6d-8812-866c1d3eae31/java:annotations(jetbrains.mps.jchr.runtime/)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
   </imports>
   <registry>
     <language id="f3061a53-9226-4cc5-a443-f952ceaf5816" name="jetbrains.mps.baseLanguage">
diff --git a/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/unification.mps b/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/unification.mps
index 55b2e4c9..a98d4ad7 100644
--- a/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/unification.mps
+++ b/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/unification.mps
@@ -18,7 +18,7 @@
     <import index="wyt6" ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065/java:java.lang(JDK/)" />
     <import index="45ys" ref="r:7365f7fe-12e6-4229-8901-f6dc6d5df03f(jetbrains.mps.logic.reactor.logical)" />
     <import index="qrld" ref="r:2a79c8aa-e372-4c00-8d71-5d7f3db517e4(jetbrains.mps.logic.reactor.constraint)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
   </imports>
   <registry>
     <language id="f3061a53-9226-4cc5-a443-f952ceaf5816" name="jetbrains.mps.baseLanguage">
diff --git a/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/var.mps b/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/var.mps
index dd4246ea..93dce6de 100644
--- a/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/var.mps
+++ b/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/var.mps
@@ -13,7 +13,7 @@
     <import index="wyt6" ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065/java:java.lang(JDK/)" />
     <import index="f8dg" ref="b984ee52-f34d-4b6d-8812-866c1d3eae31/java:annotations(jetbrains.mps.jchr.runtime/)" />
     <import index="qrld" ref="r:2a79c8aa-e372-4c00-8d71-5d7f3db517e4(jetbrains.mps.logic.reactor.constraint)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
   </imports>
   <registry>
     <language id="f3061a53-9226-4cc5-a443-f952ceaf5816" name="jetbrains.mps.baseLanguage">
diff --git a/languages/jetbrains.mps.logic/sandbox/models/jetbrains/mps/unification/sandbox.mps b/languages/jetbrains.mps.logic/sandbox/models/jetbrains/mps/unification/sandbox.mps
index 3c91bd59..1c38ea7c 100644
--- a/languages/jetbrains.mps.logic/sandbox/models/jetbrains/mps/unification/sandbox.mps
+++ b/languages/jetbrains.mps.logic/sandbox/models/jetbrains/mps/unification/sandbox.mps
@@ -11,7 +11,7 @@
     <import index="ie8e" ref="r:ab2605ab-b4bc-4e80-a8ca-19a4a8465c01(jetbrains.mps.logic.atom)" />
     <import index="33ny" ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065/java:java.util(JDK/)" />
     <import index="eifs" ref="b984ee52-f34d-4b6d-8812-866c1d3eae31/java:runtime(jetbrains.mps.jchr.runtime/)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
     <import index="wyt6" ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065/java:java.lang(JDK/)" implicit="true" />
   </imports>
   <registry>
diff --git a/languages/jetbrains.mps.logic/sandbox/runner/models/jetbrains/mps/logic/sandbox/runner.mps b/languages/jetbrains.mps.logic/sandbox/runner/models/jetbrains/mps/logic/sandbox/runner.mps
index 2f90e51a..79b183e0 100644
--- a/languages/jetbrains.mps.logic/sandbox/runner/models/jetbrains/mps/logic/sandbox/runner.mps
+++ b/languages/jetbrains.mps.logic/sandbox/runner/models/jetbrains/mps/logic/sandbox/runner.mps
@@ -14,7 +14,7 @@
     <import index="guwi" ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065/java:java.io(JDK/)" />
     <import index="eifs" ref="b984ee52-f34d-4b6d-8812-866c1d3eae31/java:runtime(jetbrains.mps.jchr.runtime/)" />
     <import index="qrld" ref="r:2a79c8aa-e372-4c00-8d71-5d7f3db517e4(jetbrains.mps.logic.reactor.constraint)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
   </imports>
   <registry>
     <language id="f3061a53-9226-4cc5-a443-f952ceaf5816" name="jetbrains.mps.baseLanguage">
diff --git a/languages/jetbrains.mps.logic/test/models/jetbrains/mps/logic/test/unification.mps b/languages/jetbrains.mps.logic/test/models/jetbrains/mps/logic/test/unification.mps
index 888fa57a..80aaf773 100644
--- a/languages/jetbrains.mps.logic/test/models/jetbrains/mps/logic/test/unification.mps
+++ b/languages/jetbrains.mps.logic/test/models/jetbrains/mps/logic/test/unification.mps
@@ -17,7 +17,7 @@
     <import index="33ny" ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065/java:java.util(JDK/)" />
     <import index="45ys" ref="r:7365f7fe-12e6-4229-8901-f6dc6d5df03f(jetbrains.mps.logic.reactor.logical)" />
     <import index="qrld" ref="r:2a79c8aa-e372-4c00-8d71-5d7f3db517e4(jetbrains.mps.logic.reactor.constraint)" />
-    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.constraint)" />
+    <import index="95zw" ref="r:f3ff7852-b9dd-4760-b213-a8a031c77d0e(jetbrains.mps.logic.jchr.predicate)" />
   </imports>
   <registry>
     <language id="f3061a53-9226-4cc5-a443-f952ceaf5816" name="jetbrains.mps.baseLanguage">